Device for pulverizing alpha mixture of air and liquid fuel



April 6,1926. 7

- L. GRILLET DEVICE FOR PULVERIZING A MIXTURE OF AIR AND LIQUID FUELFiled Jan. 5 1925 j m 0 5 Q flu 1 f 1 0 5 M 3 m m A /N W 1 H m m L 5 m m(WU-J fly .1 9 O msvaivvvvvk m w P- O O 5, .7 l uwv u .1 .9 I a F letented Apr. 6, 1926.

urine TAlES FFEQE LUCIEN GRILLET, F LAUSANNE, SWITZERLAND.

DEVICE non runvnalzlno A MIXTURE or AIR AND LIQUID FUEL,

Application filed January 5, 1925.

To all whom it may concern:

Be it known that I, LUOIEN GRILLET, a

citizen and resident of Lausanne, Switzer:

ing and pulverization being efi'ected in the ill burner. Installationsof this typevhave the double disadvantage of requiring expensivecompression devices and of Wearing out the burners by reason of thecorrosion dueto the intense combustion offthe mixture of air and fuel atthe outlet from the nozzle itself of the burner.

The present invention has for its subject a method and device forpulverizing a mixture of air and liquid fuel for the purpose ofsupplying a burner,the arrangementof the device being such that theinstallation for the production of air under pressure may beconsiderably reduced by reason of the fact that a low pressure and asmall supply of air suffices to ensure the operation of the device. Acharacteristic feature of the in vention resides in the fact that themixture of fuel and compressed air comes into operation on entering thepulverizer, for example,

in a single passage terminating in a pulverizer forming a part of theburner. The gasous mixture is not ignited immediately on leaving thepulverizer by reason of the high speed of the fuel mixture when leavingthe nozzle. The flame is formed at a point where the speed of flow ofthe mixture becomes equal to the speed of propagation of the flame forthe combustiblemixture under consideration. In this manner the cause fordeteriorating the nozzle, referred to above, .is eliminated. a 1

In the accompanying drawing there is also illustrated diagrammaticallyand'solely by of example a form of construction 'of' a deviceconstructed in accordance with the invention and applied to aninstallation for heating afurnace.

Figure 1' is a diagram ofthewhole of the pulverizing installation,

Serial No. 738.

Figure 2 shows to a larger scale and in longitudinal section, a detailof the burner, and

Figure 3 also shows a longitudinal section and to a still larger scale adetail of the preliminary mixing chamber which constitutes thecharacteristic feature of the invention.

The installation illustrated comprises a tank 1 enclosing liquid fuel(masout for example). This tank is provided Witha filling aperture 2 anda gauge 3 serving to indicate the pressure.

A motor-compressor group of low power suffices to supply the necessaryair under pressure. This group comprises a motor 4: (an electric motorof the low power type) connected, for example, by a transmission belt 5,to a small compressor ofthe vertical piston type similar to that usedfor inflat- M ing pneumatic tyres on automobile vehicles. For aninstallation of-the currenttype the power of the motor-compressor groupis about one-quarter horse-power. The compressed air is passed through apipe 7 into the masout tank 1 so as to cause this-to be compressed intothe pipes. From the tank 1 the compressed air passes out through anadjustable safety valve, mounted on the fitting 8, and is conducted by apipe 9 into an expanding device 10 connected by the pipe 11 to aspraying device 12 for effecting a mixture of air and fuel. l i

The fuel in the tank 1 passes through the passage 13 into a temperatureexchanging device comprising a coil 14 disposed in the casing of thecompressor 6, for the purpose .of heating the fuel and recuperating theheat which is disengaged in the compressor.

The fuel is thus rendered more fluid. 7 From the temperature exchangingdevice the fuel the cook 16 for the fuel and of the cook 17 forthecompressed air. The compressed air draws the fuel with it into thesingle mixing tube 18 of very small internal diameter, (this diameterbeing'of the order of 1 millimeters). The pipe 18 terminates in apulverizer 19 forming part of a burner 20 secured in the Wall 21of thefurnace to be heated.

The pulverizer 19 consists of a chamber 22 in which terminates the en hh is ill preferably enlarged, of the pipe 18. The wall of the chamber 22opposite the pipe 18 is etliciently levelled and its surface is at rightangles to the axis of the burner; This wall is provided with an orifice:23, abso lutely in the centre, forming the outlet nozzle tor thecombustible mixture. In the interior of the chamber 22 is disposed apulverizing cartridge 24: which may be placed against the wall of thechamber or may be disposed at a cer ain distance from this wall. Thecartridge Q-t may be cylindrical. but it is preferably of the shapeshown in Figures 2 and 3. in these figures it is formed of two truncatedcones connected together at their smalllnlses. Its outer diameter issubstantially equal to the external diameter of the chamber 2?. which itenters without. triction" and in which it can turn. The two outer taces'ot the cartridge Ql are made per'lectly smooth and at right angles tothe axis of the burner. 1n the surface thereof are provided two or morehelicoidal grooves. These two points constitute the. two characteristicfeatures of the pulverizing cartridge. This can turn in the interior ofthe chamber or may be fixed by any suitable means to a suitable point ofthe said chamber.

The device described is secured to the screw ot the nozzle by means of asupport 26 held in position by the screw 2?. The admission ofsupplementary air is adjusted by means of av deflector 28. The systemoperates in the following manner.

When starting the motor -lt the compressor (3 't'orces air underpressure through the pipe 7 into the fuel tank 1. The liquid fuel underthe action ot the pressure of the air passes through the pipe 13 intothe heat recuperating device 1 1- and from this into the spraying device12 which it reaches in a heated condition and consequently in a morefluid condition. The compressed air in excess pas-es from the tank 1through the valve 8, along the pipe 9 and after passing through the tansion device 10 it also reaches the spr vmg device 1'3 by means of thepipe 11. The cock 1? is first slightly opened and this enablescompressed. air to pass into the pipe 18. By reason of the vacuum thusproduced the air dra with it drops of fuel which tlSO enter the mixingpipe 18 after the cock 3 has been opened. The air and fuel are mixedtogether in the said pipe 18 and in he chamber are subjected to aparticularly tti ient mechanical pulverization by the :rtridge 2i. Theair and fuel intimately ixcd together pass through the orifice in heterm of a jet oit fine spray, each particle air being mixed with aparticle of liquid by reason of the passage through the pulverizer.\Vhen leaving the nozzle the pressure, although relatively low, ismeanwhile sutiicient so as to cause the air to considerably increase invohime. This causes the mass of fuel to be divided into extremely fineparticles. The gaseous mixture projected at a high speed through thenozzle into the interior of the furnace where it is ignited by contactwith a spark or with a flame producing a long bluish white flame whichgives a very intense heat. This tlame is generated at arelatively largedistance (of the order of to S centimeters) from the outlet. orifice otthe pulverizcr. At this point the speed oi [low of the fuel mixture isvery high. By reason ot the increase in volume of the mixture suppliedthrough a very small section at the outlet tro'i'n the pulverizer, thespeed of flow diminishes in proportion to the ejecting tone. Thesupplementary oxygen necesszuw l'or combustion is introduced iiitirtlieburner in lhe form of air through an opening 25 at the rear or theburner and its admission may be adjusted by the deflector The stabilityof the gaseous lnixture is obtained by the adjustment; of the cocks 1Gand 17 which for this purpose are provided with graduations.

The stopping of the device effected by stopping the compressor group andby closing the cooks 1G and 17.

The combustion is complete without the evolution of smoke, withoutleaving any l'cSltlltt and withoutrequiring for this purpose anyappreciable excess of air. It presents the maximum of security forcontinuous operation and it only requires installations of slightimportance for the product ion of air under pressure.

For protecting the walls of the furnace against corrosion by the flamethis may be concentrated on a refractory body placed on the grid andforming at the same time a heat accumulator.

It will be understood that the device above described may be applied toall suitable controlling apparatus tunctioning as a servo-motor andpermitting ot obtaining automatic operation.

The supply of gaseous mixture depends upon the section of the orifice Q3of the pulverizer 19. For increasing this supply it sutlices to enlargethe said orifice by very small proportions.

Having thus described my invention what I claim as new and desire tosecure by Let ters Patentis: v

1. A heating device for the purpose spccified comprising a small aircompressor, a heat recuperating device on said compressor, a fuel tank,a pipe leading from the bottom of said tank to said heat recuperatingdevice, a pipe leading from the compressor to the top of the tank, saidcompressor forcing air under pressure into the tank whereby the fuel ispassed into the heat recuperating device, a spraying device, a pipeleading from the heat recuperating device to said spraying device, meansconnecting said spraying device to the top of the tank, an outlet pipeleading from said spraying device, said outlet pipe being of small diameter, a burner, a pulverizing device in said burner and connected to thesaid outlet pipe, said pulverizer being adapted to discharge apulverized mixture of air and fuel into the burner, and adjustable meansfor supplying supplementary air to said'burner.

2. A device for supplying burners for furnaces With liquid fuelcomprising a motor, a compressor, means connecting the compressor to themotor, a fuel tank, a delivery pipe connecting the compressor to thefuel tank, an air expansion device, a pipe connecting the top of thefuel tank to the air expansion device, a combined spraying and mixingdevice, a pipe connect ing said combined spraying and mixing device Withthe air expansion device, a heat recuperating device mounted on thecompressor, a pipe leading from the bottom of the fuel tank to saidrecuperating device, a pipe leading from said recuperating device tosaid combined spraying and mixing device, means for controlling thepassage of fuel and air under pressure into said combined spraying andmixing device, a single outlet pipe of small diameter leading from saidcombined spraying and mixing device, a pulverizing chamber mounted atthe end of said outlet pipe, a pulverizing device inside said chamber,said pulverizing device consisting of two truncated cones having theirsmall bases connected together, said pulverizing device having aplurality of helicoidal grooves therein, said pulverizing chamber havingan orifice of small cross section in its Wall opposite to the Wallconnected to the said out let pipe, a burner member, means forsupporting said pulverizing chamber in said burner member and means foradjusting the supply of supplementary air to said burner member.

LUCIEN GRILLET.

